The sexy Twilight costars stopped by the Ellen DeGeneres Show to discuss the final flick in the four-year franchise, and Rob coyly confesses that he has yet to see Breaking Dawn Part 2 (shame on you, Mr. Pattinson!).

Ellen, who has seen the movie, reveals that the ending is different from the books, but Lautner takes the lead and insists fans won't be disappointed:

"I would be really scared if you were really pissed at us right now, but I don't think fans will be upset with it," the shape-shifting werewolf tells Ellen. "We don't change anything. I mean, the books are their babies; we can't really touch it too much. It's fun and there is a definitely a twist."

The costars also note that Breaking Dawn parts 1 and 2 were filmed back-to-back, and Rob can't help but take a little dig at Mr. Lautner as they discuss the complicated production process:

"The first one [Twilight] and the second one [New Moon] was the biggest gap," Rob says of the franchise filming. "The gap between the first [film] and the second one, that was when Taylor…Taylor left the first film a 15-year-old little boy with a long wig and he came back like a Chippendale."

Also up for discussion? Rob's adopted dog, Bear, and the animal lover is adorable while discussing his precious pooch:

"Yeah, he [Bear] was in a five-day kill shelter and it was on his fourth day," he tells Ellen of the adoption process. "A couple of days a later just by coincidence I had to go back to L.A. and this is not my usual way of traveling but we had like a private plane. So I took him from the worst pound in Monroe, Louisiana, and he was sitting on a little private jet the next day."

And if that's not enough to make you love Rob even more, then watch the dude get bashful when Ellen gives him a tough time for always having his fly down:

"Don't you check right before? Ellen asks. "We have another picture of you walking. I think it was a Halloween shot and the zipper is down…And you had a mask on, but we know it was you because your zipper was down."